The present disclosure generally relates to steam turbines and more particularly to systems and methods for steam turbine remote monitoring, calculating corrected efficiency, monitoring performance degradation, diagnosing and benchmarking.
Monitoring steam turbine efficiency is critical for performance and cost effectiveness. Steam turbine performance is monitored at test conditions during initial performance evaluation and commissioning checks. This performance monitoring is often carried out with the help of precision sensors specially mounted in specific locations to give more accurate readings of sensor data. Performance monitoring of a steam turbine can be repeated at regular intervals using measured data or time-based methods. Determining the thermal performance on a continuous basis is important for improving plant heat rate because it provides the ability to track changes due to day-to-day events such as operational variations. Thermal performance for fossil fueled power plants depends on boiler efficiency and turbine cycle performance.
When steam turbines are installed and delivered, thermal performance tests are conducted using precision sensors to demonstrate if the equipment satisfies contractual requirements. Additional tests are conducted periodically at different operating intervals to check for any performance shortfalls. After installation and delivery, plant performance tools calculate the deviations between current or actual efficiency of the equipment. In general, the expected performance at rated conditions using industry standards (ISO, ASME PTC, DIN etc) are implemented as performance monitoring guidelines. The deviations between actual and expected performance data are used to monitor short- and long-term equipment degradation and can be used to make service recommendations to improve turbine performance. All the above tests are conducted during special test periods and are not performed during routine operation of the turbine.
For the tests discussed above, the unit must be operated at specified conditions within allowable operational variation bands. Any additional efficiency measurement tests typically require expensive instrumentation and restrict operational flexibility. Hence, using the above-described methods, it is not possible to trend unit efficiency.
Furthermore, turbine failures can result in large economic losses. Presently, individual steam turbines are monitored for only critical performance parameters using field sensor data providing general health statistics. In general, there is no way to determine in-depth operational characteristics and compare or baseline a unit's performance with respect to the other units of the same configuration or design type. Although analyzing a single unit's performance can provide insight into a steam turbine's actual performance, the monitoring and diagnostics center typically needs additional information across the installed fleet to troubleshoot performance degradation issues related to a particular design type or configuration to assist in validation of new steam turbine designs, and provide feedback to the design engineering group.
Therefore, systems and methods are needed not only to continuously evaluate steam turbines but also to baseline a unit's performance on a fleet and determine the source of operational deviations, such as particular design type and operational anomaly.